Add project files.

DIDemoLib/Messages.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace DIDemoLib
+{
+    public class Messages : IMessages
+    {
+        public string SayHello() => "Hello Viewer";
+        public string SayGoodBye() => "Goodbye, farewell and good day!";
+    }
+}